In CSV universal import, withdraw field is expected to be a positive number. But some banks have this field as a negative number. Which would require the user to manually change all the negative values to positive values.
There are two possible solutions to this:
1) strip the negative sign from the withdraw field when reading it.
2) have a 'negative withdraw' field type, that would expect the the number to be a negative value.
I think the 1st solution would be the least confusing.